A Fresh Air Subwoofer is a type of subwoofer used in automobiles. It is proprietary, patented technology and uses a calculated enclosure/port arrangement to the outside to handle the rear sound wave from the loudspeaker. The first implementation was on the 2015 Volvo XC90, produced by Alpine Electronics.
Compared to a standard subwoofer the size is reduced significantly while giving improved low frequency performance.
Inventor of the technology is Vel Zelican. Various patents related to the technology are held by Blueprint Acoustics and Alpine Electronics.